1. Field of the Invention
The present invention relates to multimedia communications networks and, more specifically, to playlist recovery systems.
2. Description of the Related Art
Recent advances in digital-multimedia-content (DMC) compression, storage, and distribution technologies have led to the availability of hundreds of channels of multimedia services (e.g., movies, live broadcasts, infomercials, advertisements, and music) to the average consumer via satellite direct-to-home (DTH), digital cable, over-the-air (OTH) broadcast high-definition television (HDTV) systems, and broadband Internet.
As the number and variety of multimedia services increase, so does the need to manage the “on-air” aspects of this content. For example, as part of their service offerings, Home Box Office (HBO) (a division of Time Warner Inc.) supplies multimedia programs (e.g., “The Sopranos” and “Sex and the City”) via satellite uplink and other high-speed transport systems to service providers (e.g., cable and DTH satellite providers) around the world. With so many paying subscribers viewing their content, HBO and other multimedia service providers have an obligation to minimize interruptions or errors in the streaming of this content from their on-air facilities.
A typical content sourcing facility (e.g., on-air facility for video services) typically includes a redundant cluster of content (e.g., video and audio) sources ultimately feeding an on-air source selector that feeds an uplink transponder or broadband network interface. These content sources commonly include a combination of tape players, live broadcast feeds, and digital video servers. An on-air manager typically is employed to manage a playlist that describes the title, duration, and start/stop times of various pieces of multimedia content or program segments. The playlist is effectively a master document that describes what is played, when, and in what sequence. This list includes not just entries corresponding to relatively long-duration movie or program segments, but also commercials, shorts, and commercial insertion opportunities. It also includes various text, audio, and video segment overlay sequences corresponding to overlap intervals between program segments. The latter includes the well-know “squeeze-and-tease” intervals where, for example, the trailer or credits at the end of one program segment are scaled to a fraction of the screen size and displayed simultaneously with the start of a subsequent program that is scaled to the remaining available screen.
It is common for a playlist to be supported by various editing applications that allow a user to make routine maintenance, or last-minute rush modifications, to the on-air program sequence. Such modifications, especially the last-minute variety, can sometimes result in corruption of the playlist. Additionally, failure of the video content sources (e.g., tape players, pre-recorded media players such as DVD players, and video servers) and/or infrastructure (e.g., switchers, routers, or time-base generators) can lead to the need to recover, edit, and restart a playlist. The process of calculating and restarting a content stream on a backup server or tape unit via correction and reinstantiation of a playlist is called “playlist chasing.”
Until recently, the limited number of content channels, as well as the nature of the content sources (e.g., tape playback units), made the task of maintaining and fixing errors in the playlist (i.e., playlist chasing) manageable without significant automation. However, as the variety and number of concurrent streams increase, and the content sources change from easily manageable resources, such as tapes, to less directly manipulable sources, such as video servers, the need has become acute for a system to manage and automatically correct playlist errors.